Silver Smelting Process of JBR, West Bromwich, UK Dried/calcined sludge & residues
are mixed with ashes and recycled dusts,
and are smelted in a coke fired blast furnace.
The blast furnace comprises a vertical,
water-cooled shaft, into the top of which
the silver bearing mix is charged. Slag,
flux, litharge and coke are also charged
with the materials. Lead, in the form of
recycled litharge, is used as the metal
collector to form a lead-silver alloy.
At the base of the furnace is a brick-lined
removable crucible in which slag and metal
alloy are continuously separated. Oxygen-enriched
air is blown in close to the base of the
furnace and this provides the high temperature
combustion of the coke necessary for smelting.
The furnace operates with the smelting zone
at ~1400°C. The hot exhaust gases pass
up the furnace, through the charge material
and, by direct heat exchange, pre-heat the
charge materials.
The furnace gases, laden with dust, fume,
and moisture exit the top of the furnace
and are ducted to a dry, fabric bag filter
plant before discharge through a 55 metre
stack to atmosphere. Metallurgical fume
and dusts are removed by the filter - this
method is recognised as BAT by EA. The gas
stream is neutralised to avoid acidity by
the lime added to the by-products of the
processes.
Emissions to atmosphere are continuously
monitored by a particulate monitor and the
data logged onto an on-line computer. Frequent
additional sampling of the exhaust stack
also monitors for emissions of gaseous and
fume products.
Dusts from the filter are collected into
stirred mixing tanks and, by the addition
of water and lime, halides are converted
to soluble calcium salts. The insoluble
heavy metal compounds are separated by filter
press and are recycled to the blast furnace.
This process is fully automated.
The solution containing the soluble salts
is either discharged to drain in accordance
with the requirements of our Consent to
Discharge or, alternatively, it can be removed
from site by tanker and treated by specialist
effluent contractor to the requirements
of the Environment Agency. |
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JBR Recovery Ltd is one of the UK and Europe's leading silver recovery and precious metal recycling specialists. We handle precious metal recovery, silver recovery , gold refining, platinum refining, silver smelting, photographic waste recycling and recovery and good delivery 999 refined silver. |